Mononuclear carbonyl manganese(I) and molybdenym(II) complexes with chelating biimidazole,bibenzimidazole or tetramethylbiimidazole ligands

The preparations and properties are described of novel anionic and neutral mononuclear biimidazolate (biim), bibenzimidazolate (bibzim), or tetramethylbiimidazolate (tmbiim) manganese(I) and molybdenum(II) complexes of the type [Et₄N][Mn(CO)₂L₂(bibzim)] (L = P(OEt)₃); [Et₄N][Mo(η⁵-C₅H₅)(CO)₂-(N)₂] ((N)₂²⁻ = biim²⁻, bibzim²⁻ tmbiim²⁻); [Mn(CO)_4−nL_n{H(N)₂}] (n = 1; H(N)₂⁻ Hbibzim⁻; L = P(OMe)₃, PEt₃), (n = 2; H(N)₂⁻ = Hbiim⁻, Hbibzim⁻; L = P(OPh)₃, P(OMe)₃, P(OEt)₃, P(OⁱPr)₃; [Mo(η⁵-C₅H₅)(CO)₂{H(N)₂}] (H(NN)₂⁻ = Hbiim⁻, Hbibzim⁻, Htmbiim⁻, in which the heterocyclic anions act as bidentate chelate groups. Treatment of the anionic complexes with MeI gives neutral derivatives of general formula [Mn(CO)₂L₂(Mebibzim)] (L = P(OMe)₃, P(OEt)₃) and [Mo(η⁵-C₅H₅)(CO)₂{Me(N)₂}] (Me(N)₂⁻ = Me-biim⁻, Mebibzim⁻, Metmbiim⁻. Cationic manganese(I) complexes of the type [Mn(CO)_4−nL_n{H₂(N)₂}][ClO₄ (n = 1; H₂ (N)₂ = H₂bibzim; L = P(Ome)₃, PEt₃), (n = 2; H₂(N)₂ = H₂biim, H₂bibzim; L = P(OPh)₃, P(OMe)₃, P(OEt)₃, P(OⁱPr)₃) have also been obtained by treating the corresponding neutral complexes with HClO₄. The structures of the complexes have been elucidated by molecular weight determinations, conductance data, and IR spectroscopy.     

Zur kenntnis der chemie der metallcarbonyle und der cyanokomplexe in flüssigem ammoniak : XXXIII. Über die darstellung neuer carbamoylcarbonyl-komplexe aus bekannten und neuen kationischen carbonylverbindungen des mangans und rheniums

The covalent carbamoyl carbonyl compounds Re(CO)₅COHN₂, cis-M(CO)₄(L)CONH₂, M(CO)₃(L)₂CONH₂ and M(CO)₃(D)CONH₂ (M = Mn, Re; L = PPh₃, PEt₃; D = bipy, phen) are formed by reactions of the cationic complexes [Re(CO)₆]⁺, [M(CO)₅L]⁺, [M(CO)₄L₂]⁺ and [M(CO)₄D]⁺ (M = Mn, Re; L = PPh₃, PEt₃; D = bipy, phen) with liquid NH₃ with concomitant deprotonation: [M(CO)_6?nL_n]⁺ + 2 NH₃ → M(CO)_5?nL_nCONH₂ + NH₄⁺ (n = 0, 1, 2) and [M(CO)₄D]⁺ + 2 NH₃ → M(CO)₃(D)CONH₂ + NH₄⁺ The stability of the above-mentioned carbamoyl carbonyl complexes increases from the penta- to the tetra- to the tri-carbonyl derivatives. In all cases the rhenium compounds are much more stable than the corresponding manganese complexes. Whereas the carbamoyl compound Re(CO)₄(PEt₃)CONH₂ can be isolated by reaction of [Re(CO)₅PEt₃]⁺ with NH₃, the corresponding manganese complex undergoes Hofmann degradation of amides even at ?70°C to form HMn(CO)₄PEt₃ and NH₄NCO. The IR and some mass and ¹H NMR spectra of the new hexacoordinated carbamoyl carbonyl complexes are discussed and the reactions of these compounds with liquid NH₃, HCl and CH₃OH are described.     

Rate-structure correlations for migratory CO insertion. Steric acceleration for the octahedral iron(II) case

The kinetics of the migratory insertion reaction of cis,cis-[(diars)- Fe(CO)₂L(Me)]⁺, (Ia–Ig), (L = C₆H₁₁O₃P (ETPB), P(OMe)3, PhP(OMe)₂, PMe₃, PhPMe₂ Ph₂OMe) or Ph₂PMe) in the presence of excess L′ (L′ = P(OMe)₃ or i-C₃H₇NC) in methylene chlorine-d₂ to form [(diars)- Fe(CO)LL′(C(O)Me)]⁺, (IIa–IIg), follow the rate law: Rate = k_insert [(I)]. The first order rate constant, k_insert, depends primarily on steric factors and shows an overall increase of a factor of 270 (at 290 K) as L varies from ETPB (cone angle 101°) to Ph₂PMe (cone angle 136°). The pronounced steric acceleration of insertion rate is in accord with a unimolecular rate determining insertion step which requires neither inter- nor intramolecular nucleophilic participation.     

An investigation into the mechanism of conversion of fac-[Mn(CO)3{P(OMe)2Ph}2X] (X = Cl Br) into mer-cis-[MnCO2{P(OMe)2Ph}3X] in the presence of P(OMe)2Ph

The complex mer-trans-[Mn(CO)₃{P(OMe)₂Ph}₂X] (X = Cl, Br) is an intermediate in the conversion of fac-[Mn(CO)3{P(OMe)₂,Ph}₂,X] into mer- cis-[Mn(CO)₂{P(OMe)₂Ph}₃X] in the presence of P(OMe)₂Ph in benzene. No direct route between the latter two complexes could be detected kinetically. The results imply a trans carbonyl disposition as a prerequisite for higher carbonyl substitution in octahedral Mn¹ carbonyl complexes.     

Novel heterobimetallic complexes with S2CPR3(κ-S,S′)(κ-S,C,S′) bridges. X-Ray structure of [MnMo(CO)6(μ-Br)-(μ-S2CPiPr3)]

Reaction of fac-[Mn(CO)₃(S₂CPR₃)(Br)] with [Mo(CO)₃(NCMe)₃] produces a member of a novel class of heterodinuclear complex [MnMo(CO)₆(μ-Br)(μ-S₂CPR₃)] (R = Cy, ⁱPr), which contains S₂CPR₃ bridging ligands, acting as an (κ-S,S′) chelate towards Mn, and as an (κ-S,C,S′) pseudoallyl group to Mo, without a direct MoMn bond. One carbonyl group in [MnMo(CO)₆(μ-Br)(μ-S₂CPR₃)] can be easily displaced at room temperature by neutral ligands such as PEt₃ and P(OMe)₃, affording pentacarbonyl complexes, [MnMo(CO)₅(L)(μ-Br)(μ-S₂CPR₃].     

Methyl- and phenyl-bis(tertiary phosphine) N-bonded carboxamido complexes of platinum(II)

Methyl- or phenylN-carboxamido-complexes of platinum(II) Pt(NHCOR')RL₂ (L = PEt₃, R = Me, R′ = Me, CH = CH₂; L = PEt₃, R = Ph, R′ = Me; L = PMe₂Ph, R = Ph, R′ = Me, Ph; L = PMePh₂, R = Ph, R′ =₃, R = Ph, R′ = Me) have been prepared by the reaction of KOH with cationic nitrile complexes [PtR(NCR′)L₂]BF₄. Thermally unstable hydrido-N-carboxamido-complexes could be detected spectroscopically. IR and NMR (¹H, ³¹P) spectra of some of the complexes indicate the existence of a solvent- and temperature-dependent equilibrium between syn-and anti-isomers arising from restricted rotation about the NC bond of the carboxamido-group. The anti-isomer is favoured by nonpolar solvents and by increasing bulk of L. In the complex [PtH(NCCH CH₂)(PEt₃)₂]BF₄, IR and NMR spectra show acrlonitrile to be bound through nitrogen, not through the olefinic CC bond.     

Reactions of M2Cl4(PR3)4 (M  Mo and W) with carbon monoxide

The reactions of M₂Cl₄(PR₃)₄ derivatives (M  Mo, W and PR₃  PEt₃, PBu₃ⁿ) with CO at atmospheric pressure in toluene at 70°C to afford M(CO)₃(PR₃)₂Cl₂ and trans-M(CO)₄(PR₃)₂ are reported.     

Control of Light‐Promoted [2+2] Cycloaddition Reactions by a Remote Ancillary Regulatory Group That Is Covalently Attached to Rhenium Rectangles

The high‐yielding self‐assembly of three neutral rhenium(I) rectangles, [Re₂(CO)₆(L)(bpe)]₂ ( 1 a , L=2,2′‐biimidazolate (biim); 1 b , L=2,2′‐bisbenzimidazolate (bbim); 1 c , L=2,2′‐bis(4,5‐dimethylimidazolate) (bdmim); bpe=trans‐1,2‐bis(4‐pyridyl)ethylene), under hydrothermal conditions is described. The rectangles were structurally characterized by spectroscopic techniques and further confirmed by single‐crystal X‐ray diffraction. Upon irradiation with a Hg lamp at 365 nm, the bpe ligands of rectangles 1 a and 1 b underwent [2+2] photocycloaddition reactions to produce [{(Re(CO)₃)₂L}₂(4,4′‐tpcb)₂] ( 2 a , L=biim; 2 b , L=bbim; 4,4′‐tpcb=1,2,3,4‐tetrakis(4‐pyridyl)cyclobutane) through a single‐crystal‐to‐single‐crystal (SCSC) transformation. However, rectangle 1 c , which contained methyl groups on the 2,2′‐biimidazolate ligand, failed to undergo cycloaddition, even after prolonged irradiation. This result indicates that the light‐induced cycloaddition reaction can be preferentially controlled by the remote regulatory substituents, which are attached onto the same backbone of the rectangle complex. This transformation is the first reported utilization of a remote ancillary regulatory ligand that is covalently attached onto a coordination compound to control the [2+2] cycloaddition reaction.     

Preparation and characterization of mono-cyclopentadienylvanadium dihalide bis-phosphine complexes; crystal structure of (η5-C5H5)VCL2(PMe3)2

Mono-cyclopentadienyl complexes CpVX₂(PR₃)₂ and Cp′VX₂ (PR₃)₂ (Cp = η⁵- C₅H₅; Cp′ = η⁵-C₅H₄Me; R = Me, Et; X = Cl, Br) have been prepared by reaction of VX₃(PR₃)₂ with CpM (M = Na, T1, SnBuⁿ3, 1/2 Mg) or Cp′Na. Attempts to prepare analogous complexes with other phosphine ligands, PPh₃, PPh₂ Me, PPhMe₂, Pcy₃, DMPE and DPPE failed. Reduction of CpVCl₂(PEt₃)₂ with zinc or aluminium under CO (1 bar) offers a simple method for the preparation of CpV(CO)₃(PEt₃). The crystal structure of the trimethylphosphine complex CpVCl₂(PMe₃)₂ is reported.     

Coordinatively unsaturated alkyne complexes: synthesis of mono and bis-alkyne complexes of tungsten (II)

[WBr₂(CO₄]_n reacts with alkynes to give complexes [WBr₂CO(RCCR)₂]₂ (1) (R = R′ = Me, Et, Ph; R = Me, R′ = Ph), which react with nucleophiles L{L = CNBu^t, PPh₃, or P(OMe)₃} to give monoalkyne derivatives (WBr₂(CO)(RCCR′)L₂](2). An intermediate bis-alkyne adduct [WBr₂CO(MeCCMe)₂(CNBu^t)] (3) was isolated in the reaction of [WBr₂CO(MeCCMe)₂]₂ with CNBu^t illustrating that cleavage of the dimer (1) is the first stage in these reactions.     

Synthesis of ylideplatinum(II) complexes via α-functionalised alkylplatinum(II) intermediates and some comparative data on palladium(II) complexes; X-ray structure of trans-[Pt(CH2PEt3)I(PEt3)2]I

The reaction of [Pt(PEt₃)₃] with CH₂I₂ affords trans-[Pt(CH₂PEt₃)I(PEt₃)₂]I and is believed to proceed via the α-functionalised alkyl cis-[Pt(CH₂I)I(PEt₃)₂], because similar ylides are obtained from cis- or trans-[PT(CH₂X)(PPh₃)₂X] (XCl, Br, or I) with PR₃ (PEt₃, PBu₃ⁿ, PMePh₂, PEtPh₂, or PPh₃); cis-[Pd(CH₂I)-I(PPh₃)₂] does not react with excess PPh₃, but with PEt₃ yields trans-[Pd(CH₂PEt₃)I(PPh₃)₂]I; the X-ray structure of trans-[Pt(CH₂PEt₃)I(PEt₃)₂]I (current R = 0.045) shows PtP(1) 2.332(7), PtP(2) 2.341(8), PtC 2.08(2), and PtI 2.666(2) Å, and angles (a) C(1)PtI, P(1), P(2): 176.9(8), 91.6(6), 93.4(6), (b) IPtP(1), P(2): 87.1(2), 88.5(2), and (c) P(1)P(2), 166.8(3), and (d) PtC(1)P(3), 118(1)°.     

Improved syntheses of Ru(CO)2 (O3SCF3)2 (bidentate) complexes and their conversion into new [Ru(CO)2 (bidentate)2]2+ complexes

Reaction of the complexes Ru(CO)₂Cl₂L [L = 2,2′-bipyridyl (bpy) or 1,10-phenanthroline (phen)] with trifluoromethanesulphonic acid under carefully controlled conditions yields Ru[cis-(CO)₂] [cis-(O₃SCF₃)₂] (bidentate complexes. From reactions of the trifluoromethanesulphonates with the appropriate bidentate ligands, the new complexes [cis-Ru(CO)₂-L(L′)]²⁺ (L as above; L′ = 4,4′-dimethyl-2,2′-bipyridyl or 4,4′-diisopropyl-2,2′-bipyridyl) as well as the known [_cis-Ru(CO)₂L₂]²⁺ and [cis-Ru(CO)₂bpy(phen)]²⁺ have been prepared.     

Complexes containing phosphorus lignads—161: New phosphinite,phosphonite and phosphite derivatives of ruthenium,osmium and iridium

The complexes [MHCl(CO)(PPh₃)₃] (M = Ru or Os) readily undergo substitution at the site trans to the hydride ligand to afford phosphinite-, phosphonite-, or phosphite-containing products [MHCI(CO)(PPh₃)₂L] [L = P(OR)Ph₂, P(OR)₂Ph or P(OR)₃ respectively; R = Me or Et]. The ruthenium complexes alone undergo further substitution to afford complex cations [RuH(CO)(PPh₃)_nL_4?n]⁺ [n = 2, L = P(OMe)₃; n = 1, L = P(OR)₃; n = 0, L = P(OR)₂Ph or P(OR)Ph₂] which were isolated and characterised as their tetraphenylborate salts. Synthesis of the cationic complexes [IrHL₅][BPh₄]₂ [L = P(OR)₃, R = Me or Et] is also reported. Stereochemical assignments based on NMR data are given, and second order ³¹P and high field ¹H NMR patterns are analysed.     

Bridging alkyls in d-transition metal chemistry: reaction of (cod)2 RH2 (μ-R)2 with Lewis bases to give (cod)Rh(R)(L) and their reaction with aromatic hydrocarbons

Low temperatùre (−70°C) reaction of (cod)₂Rh₂2 (μ-Cl)₂ with two molar equivalents of RLi in diethyl ether gives (cod)₂Rh₂ (μ-R)₂ where R = Me, Me₃SiCH₂. Even though the bridging alkyls are air and moisture sensitive, they may be stored for prolonged periods at −30°C. The bridging alkyls are fluxional at + 20°C and the NMR spectra are consistent with a dimer of idealized D_2h symmetry. Low temperature NMR spectroscopic studies suggest that the dimers have idealized C_2v symmetry as found by X-ray studies described earlier. The bridging alkyls readily react with Lewis bases to give monomeric (cod)Rh(R)(L) where R = Me and L = PMe₃, PEt₃, P(NMe₂)₃, P(OMe)₃, py and R = Me₃SiCH₂, L = P(OMe)₃. The five coordinate, fluxional complex, (cod)RhMe(PMe₃)₂ also may be isolated. The four coordinate (cod)RhMe(PEt₃), slowly reacts with toluene to give (cod)Rh(m-tolyl)(PEt₃), (cod)Rh(p-tolyl)(PEt₃), and methane and (cod)RhMe(PMe₃) slowly reacts with benzene to give (cod)Rh(Ph)(PMe₃) and methane.     

Studien zur CH-aktivierung: II. Der einfluss der liganden auf die bildung von aryl(hydrido)ruthenium(II)- und -osmium(II)-komplexen aus aromaten

The complexes trans-MCl₂(PMe₃)₄ (M = Ru, Os) react with CO and P(OMe)₃ to give the mono- and disubstituted derivatives trans,mer-MCl₂(PMe₃)₃L (L = CO, P(OMe)₃) and all-trans-MCl₂(PMe₃)₂[P(OMe)₃]₂, respectively. On reaction of trans-RuCl₂[P(OMe)₃]₄ with CO and PMe₃, the compounds trans,mer-RuCl₂[P(OMe)₃]₃(CO) and trans,cis,cis-RuCl₂(PMe₃)₂[P(OMe)₃]₂ are synthesized. The reduction of MCl₂(PMe₃)₂[P(OMe)₃]₂ with Na/Hg in benzene or toluene via {M(PMe₃)₂[P(OMe)₃]₂} as an intermediate leads to subsequent intermolecular addition of the arene and to the aryl(hydrido)metal complexes cis,trans,cis-MH(C₆H₅)(PMe₃)₂[P(OMe)₃]₂ (M = Ru, Os) and MH(C₆H₄CH₃)(PMe₃)₂[P(OMe)₃)₂ (M = Os). For M = Ru, in the presence of P(OMe)₃, the ruthenium(0) compound Ru(PMe₃)₂(P(OMe)₃]₃ is formed. The hydrido(phenyl) complexes react with equimolar amounts of Br₂ or I₂ by elimination of benzene to produce the dihalogenometal compounds cis,trans,cis-MX₂(PMe₃)₂[P(OMe)₃]₂. The reaction of trans-RuCl₂(PMe₃)₄ with Na/Hg in the presence of PPh₃ leads to the ortho-metallated complex fac-RuH(η²-C₆H₄PPh₂)(PMe₃)₃, which reacts with CH₃I, CS₂, COS and HCl to give the compounds mer-RuI(η²-C₆H₄PPh₂)(PMe₃)₃, fac-Ru(SCHS)(η²-C₆H₄PPh₂)(PMe₃)₃, fac-Ru(S₂CO)(CO)(PMe₃)₃ and RuCl₂(PMe₃)₃, respectively. The paramagnetic 17-electron complexes [MCl₂(PMe₃)_nL_4-n]PF₆ are obtained on oxidation of MCl₂(PMe₃)_nL_4-n with AgPF₆. Their UV spectra exhibit a characteristic CT band. [RuCl₂(PMe₃)₄]PF₆ and [OsCl₂(PMe₃)₄]PF₆ react with CO and P(OMe)₃ by reduction to form the corresponding ruthenium(II) and osmium(II) compounds MCl₂(PMe₃)_nL_4-n.     

Regulation of electron donating ability to metal center: isolation and characterization of ruthenium carbonyl complexes with N,N- and/or N,O-donor polypyridyl ligands

Polypyridyl ruthenium(II) dicarbonyl complexes with an N,O- and/or N,N-donor ligand, [Ru(pic)(CO)₂Cl₂]⁻ (1), [Ru(bpy)(pic)(CO)₂]⁺ (2), [Ru(pic)₂(CO)₂] (3), and [Ru(bpy)₂(CO)₂]²⁺ (4) (pic=2-pyridylcarboxylato, bpy=2,2′-bipyridine) were prepared for comparison of the electron donor ability of these ligands to the ruthenium center. A carbonyl group of [Ru(L1)(L2)(CO)₂]ⁿ (L1, L2=bpy, pic) successively reacted with one and two equivalents of OH⁻ to form [Ru(L1)(L2)(CO)(C(O)OH)]ⁿ⁻¹ and [Ru(L1)(L2)(CO)(CO₂)]ⁿ⁻². These three complexes exist as equilbrium mixtures in aqueous solutions and the equilibrium constants were determined potentiometrically. Electrochemical reduction of 2 in CO₂-saturated CH₃CN–H₂O at −1.5 V selectively produced CO.     

A 31P and 119Sn NMR study of trichlorostannate derivatives of some chloride-bridged palladium(II) dimers

The chloride-bridged dimers [Pd(μ-Cl)(SnCl₃)L]₂ (L = P(p-tolyl)₃, P(p-C₆H₄OMe)₃, As(p-tolyl)₃, AsEt₃, PEt₃, PPrⁿ₃) have been synthesized and their ¹¹⁹Sn and, where relevant, ³¹P NMR spectra recorded. For the aryl phosphine and both arsine complexes the dimers exist as both the sym-trans and sym-cis isomers; however, for the PEt₃ and PPrⁿ₃ compounds, there is only one form, which we assign to the sym-trans structure. There is a geometric dependence of both ⁴J(¹¹⁹Sn, ¹¹⁷Sn) and ⁴J(¹¹⁹Sn, ³¹P). The dimeric complex with P(p-tolyl)₃ carbonylates 1-heptyne in the presence of excess SnCl₂, but is inactive in its absence.     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden: XI. Einige neuartige η1-vinyl-komplexe des eisens durch deprotonierung kationischer carbenkomplexe mit trimethyl(methylen)phosphoran

Novel η¹-vinyl complexes of the type Cp(CO)(L)FeC(OMe)C(R)R′ (R = R′ = H, Me; R = H, R′ = Me; L = Me₃P, Ph₃P) are obtainied via methylation of the acyl complexes Cp(CO)(L)FeC(O)R (R = Me, Et, i-Pr) with MeOSO₂F and subsequent deprotonation of the resulting carbene complexes [Cp(CO)(L)FeC(OMe)R]SO₃F with the phosphorus ylide Me₃PCH₂. The same procedure can be applied for the synthesis of the pentamethylcyclopentadienyl derivative C₅Me₅(CO)(Me₃P)FeC(OMe)CH₂, while treatment of the hydroxy or siloxy carbene complexes [Cp(CO)(L)FeC(OR)Me]X (R = H, Me₃Si; X = SO₃CF₃) with Me₃CH₂ results in the transfer of the oxygen bound electrophile to the ylidic carbon. Some remarkable spectroscopic properties of the new complexes are reported.     

A new route to mer-Tricarbonyls of manganese(I) containing N-donor chelate ligands

It has been shown that new mer-tricarbonyls mer-[Mn(CO)₃L(tmed)]ClO₄, (tmed = N,N,N′,N′-tetramethylethylenediamine, L = P(OMe)₃, P(OEt)₃, P(O-iPr)₃) can be readily obtained from the reaction between fac-Mn(CO)₃(tmed)Br, AgClO₄, and L at room temperature, whereas at 0°C fac-isomers are produced. The opposite is the case for L = CN-t-Bu; mer-[Mn(CO)₃(CN-t-Bu)(tmed)]ClO₄ is observed at 0°C, and the fac-isomer is stable at 25°C.     

31P-NMR. Measurements on Palladium-Phosphine Complexes. Nuclear overhauser effects and spin-lattice relaxation times

The ³¹P{¹H} nuclear Overhauser effects (NOE's) and ³¹P-spin-lattice relaxation times (T₁) for a series of trans-[PdCl₂P₂], P ? PEt₃, PPr₃ⁿ, PBu₃ⁿ, PMe₂Ph, PMePh₂, P(p-Tol)₃, P(cyclohexyl)₃ complexes are reported. Both the NOE and T₁ values depend upon the choice of solvent. The dipole-dipole mechanism dominates the spin-lattice relaxation of the coordinated phosphorus atom with the T₁ values for the PEt₃, PPr₃ⁿ, and P (cyclohexyl)₃ complexes decreasing with increasing molecular weight of the phosphine.